The present invention relates to a seat apparatus installed in the cabin of an aircraft.
As a seat apparatus (to be referred to as a seat as well hereinafter) of this type installed in an aircraft cabin, a reclining seat, the tilt angle of which can be changed by inclining the backrest backward, is generally used.
Recently, for example, a seat disclosed in Japanese Patent Laid-Open No. 8-258796 is proposed as a seat for the first-class section.
In order to allow the passenger to have spare room and to make him feel comfortable, this seat can take three states, i.e., a state wherein the backrest is substantially upright (actually slightly inclined backward) (normal state), a state wherein the backrest is shifted forward from this state so that it is inclined backward by a predetermined angle (reclining state), and a state wherein the backrest is further largely inclined to be set in the substantially horizontal state (bed state).
Thus, a seat which serves as a reclining seat as well as a bed is formed. This seat has a backshell covering the rear side and two sides of the seat to protect the passenger's privacy.
To incline the backrest from the substantially upright normal state to the reclining state and finally to the substantially horizontal bed state, two structures 1 and 2 are available. According to the structure 1, the seat portion is largely moved forward and simultaneously the backrest is moved forward in the interlocked manner to set the seat surface of the seat portion and the backrest surface of the backrest in one substantially horizontal surface. According to the structure 2, the seat portion is not moved forward but merely the backrest is inclined to be finally set in the bed state through the reclining state.
With the structure 1, the seat portion largely moves forward in the bed state, and accordingly a large space is needed in front of the seat.
With the structure 2 as well, the backrest is largely inclined backward, and accordingly a large space is needed behind the seat, making a back-seat passenger feel uncomfortable.
Therefore, either structure suffers large restriction when installing the seat.
In terms of human engineering, with the structure 1, when the seat portion moves forward to be set in the reclining state, a space tends to be formed between the hip and the backrest and the passenger's backbone tends to be bent, making the passenger feel uncomfortable.
With the structure 2, the backrest is largely inclined backward from the reclining state. The passenger's head is thus lowered to make him feel uncomfortable.
If the seat portion is moved forward after the backrest is set in the reclining state and the backrest in the reclining state is inclined, while being moved forward, in the interlocked manner, to be set in the substantially horizontal state, stability during motion can be improved.
When the seat portion is to be moved, if its direction (angle) is changed and the seat portion is tilted about the hip (thighs) as the center of rotation, stability during motion can be further improved.
In one of conventional aircraft seats which employs the structure 1, legs having casters are provided to a seat portion, or a trolley (Japanese Patent Laid-Open No. 8-258796) is provided to a seat portion. The seat portion is pulled forward together with the legs or trolley.
As described above, in the conventional seat, particularly a seat whose seat portion can move forward and backward, legs having casters, or a trolley is provided to the seat portion, and the seat portion is pulled out forward integrally with the legs or trolley.
If legs having casters or a trolley is provided to the seat portion, a sufficiently large space cannot be ensured under the seat portion.
Therefore, it is difficult to ensure, under the seat portion, a mounting space where driving units for driving the seat portion, the backrest, the legrest, and the like are to be mounted, and the driving units and driven members must be connected to each other through complicated links and the like.
This imposes large restriction on the driving units themselves and how to mount the driving units. Moreover, rails for the casters must be formed, increasing the number of components and the number of assembling steps.
Also, a countermeasure must be taken so the legs or trolley will not damage the floor surface or the carpet extended on the floor.